1. Field of the Invention
The present invention relates to a very soft spunbonded nonwoven fabric formed of a polyolefin.
2. Description of the Prior Art
Spunbonded nonwoven fabrics have been widely used as various types of everyday items or industrial materials because they have good mechanical properties, such as tensile strength, due to the fact that they are formed from continuous fibers, when compared with other dry or wet non-woven fabrics.
Of the various types of spunbonded nonwoven fabrics available, those made of a polyamide, such as nylon, or a polyester, such as polyethylene terephthalate, have relatively high softness. Therefore, attempts have recently been made to use them as materials which make direct contact with the human body, such as in disposable sheets or the top sheets of diapers.
However, spunbonded nonwoven fabrics made of a polyolefin are not as soft as those of other materials, although they have excellent water resistance and chemical resistance and are inexpensive, and hence their application has been limited to specific fields. Examples include use in the civil engineering field as drainage materials, in the agricultural field as covering materials, and various other specific fields as carpet bases. Of course, the application of polyolefin spunbonded nonwoven fabrics in the above-described field of materials such as the top sheets of disposable diapers has been gradually increasing, because their other properties, apart from softness, are superior to those of spunbonded fabrics made of other materials. If the softness of polyolefin spunbonded nonwoven fabrics could be improved, their fields of application can be expected to expand widely in the future because of their many other excellent properties.